Effects of Organic Manures in Changes of Some Soil Properties at Different Incubation Periods

Abstract

A laboratory incubation experiment of 60 days was carried out to observe the changes of soil pH, electrical conductivity (EC), soil organic carbon (SOC), and potassium chloride extractable nitrogen ( ) in a soil to which three animal manures viz. cow dung (CD), chicken manure (CM) and a combination of CD and CM had been applied at a rate of 10 t · ha －1 . The effects of manures varied with manure type and incubation period. Soil pH slightly increased with the incubation period up to 30 days there after it declined with time significantly (p < 0.05). There was a significant (p < 0.05) increase in EC as days of incubation increased. Organic carbon contents of manure treated soils reached its peak at 15 days of incubation and decreased thereafter with time. The content of increased significantly (p < 0.05) as incubation period increased in control and cow dung amended soils whereas there was no significant difference in contents when either chicken manure alone or cow dung and chicken manure mixed in combination. After 60 days of incubation, the highest amount of was found in cow dung plus chicken manure treated soil followed by chicken manure treatment.